Over the past three years in Cleveland, Ohio there have been 25 Cases of pulmonary hemorrhage and hemOsiderosis in young infants. Nine of the infants have died. Since November, 1994, the Centers for Disease Control and Prevention (CDC) has been investigating the Cause of this outbreak (MMWR 43:881-883,1994). All but two of these Cases have occurred within a Contiguous eight zip code area in the eastern part of the metropolitan area. Several lines of evidenCe indiCate that the most likely Causal agents are fungal toxins from a fungus called Stachybotrys atra. This somewhat unusual fungus was found in high quantity in the home environments of the affected infants but also to a lesser degree in some of the comparison homes. Stachybotrys requires water soaked cellulose to grow, and was found in homes where there had been water damage from flooding, plumbing leaks on roof leaks involving wood or paper products (e.g. insulation, gypsum board, Ceiling tile). The spores of this fungus do not germinate in the lung but do contain very potent mycotoxins which appear to be particularly toxic to the rapid growing lungs of young infants. More Cases continue to occur, a few infants having had only very subtle initial symptoms such as nose bleeds and chest congestion. Concern that there may be a larger number of undetected young infants- with this disorder, led to the examination of all infant coroner Cases over the past three years. This revealed six SIDS' (sudden infant death syndrome) Cases with major amounts of pulmonary hemosiderin laden macrophages. Since it takes about 48 hours for the macrophage to convert erythrocyte hemoglobin iron Into hemosiderin, this indicates hemosiderosis existing prior to death. All of these infants had lived in the eight zip code cluster area. The purpose of this proposal is to extend the Cleveland epidemiological investigation to a use-control stud of the SlDS/hemosiderosis Cases to see if the same home environment,fun gal exposure correlation exists. Since Cyclosporin is one of the toxins produced by Stachybotry atra, we propose to prospectively determine if this toxin is a valid exposure marker.